1. Field of the Invention
The example embodiments relate to a semiconductor device and a method for fabricating the same.
2. Description of the Prior Art
Electrical characteristics of a capacitor in a memory device, such as a DRAM (Dynamic Random Access Memory), exert a great influence on the final yield characteristics of the product. The increase of the capacitance value causes the increase of the amount of charge that is stored in the capacitor. The increase of the charge amount can improve the refresh characteristics of the DRAM and satisfy the electrical characteristics of the semiconductor device.
On the other hand, in order to increase the capacitance, a technology to form the DRAM so that the DRAM includes a stack type lower electrode has been developed. As the height of a stack type storage structure becomes higher, the cell capacitance typically increases. However, a gap between cells is narrowed, and an aspect ratio between a lower length and a height of the capacitor structure is typically increases. Accordingly, due to the thermal and mechanical stresses exerted on the electrode of the capacitor, a difference in strain between the surface and the interior of the electrode typically occurs. Due to such a difference in strain, the stack capacitor may deteriorate.